refactor to drivermanager
add driver factory
refactor drivers
update gem spec and driver
web and service bug fixes
Merge branch 'drivermanager' into develop

Conflicts:
	lib/nixonpi/drivers/bar_graph_driver.rb
	lib/nixonpi/drivers/io_driver.rb
	lib/nixonpi/drivers/power_driver.rb
	lib/nixonpi/state_machines/lamp_state_machine.rb
	lib/nixonpi_service.rb